The company will buy the methane from pig farms in North Carolina. The collected gas will be treated and sent to two of Duke’s power stations through a pipeline system.

Duke Energy says it aims to generate 0.2 percent of its power from pig waste by 2021.

“That sounds like a very small fraction, but we’re talking about a relatively new technology here,” said company spokesperson Randy Wheeless, adding that the technology and the cost would come down and such projects would become more of a mainstream source of power.

The new facility will be constructed and operated by Duke’s partner Optima KV, and begin operations by next summer.

Duke Energy provides power to 7.4 million customers in the southern US. Most of the energy produced by the company comes from coal, nuclear and natural gas. It has recently started investing in solar energy.